|Aeronautical Products A-1|
Two undergraduate engineers of the University of Michigan, Corwin Denny and Karl Schakel, with the Aeronautical Products Corporation of Detroit, Michigan, have designed and built a helicopter. Neither of the designers, however, is still with the corporation, but work is progressing on the helicopter they initiated. The ship, during preparations for a trial flight, was damaged, has been rebuilt, and is now again approaching the test-flight period.
The Denny and Schakel helicopter is a single, main-rotor machine employing an auxiliary tail rotor for torque correction. The main rotor is 9m in diameter and is powered by a ninety-horsepower engine. The gross weight of the craft is reported to be approximately 540kg. It has a fixed tricycle landing gear.
Built of welded-steel tubular construction, this helicopter is a single-seater with enclosed cabin. The pilot sits behind the engine, which is mounted in the nose. A long shaft extends under the pilot's seat and is geared to the vertical shaft of the rotor.
H.F.Gregory "Anything a Horse Can Do. The story of the Helicopter", 1944
Aeronautical Products Inc, which manufactures aircraft engine parts, continued the work on a helicopter design done before they left the firm by Corwin Denny and Karl Schakel.
The aircraft was damaged during preparations for the first trial flights, but it was rebuilt and eventually flew successfully. It was not, however, actually put into production.
In 1947 Aeronautical Products merged with the McQuay Company.
Model 3, 1944
This helicopter's fuselage, of fabric-covered welded steel tubing, resembled that of a light aircraft with the engine located in the forward section and placed horizontally forward of the cabin instead of being situated centrally, as in most helicopters.
Power from the engine, cooled by a fan mounted directly above it, was transmitted by pulleys and vee belts to a horizontal main drive shaft, then through a bevel gear drive to the main rotor shaft which passed between the pilot's and the passenger's seats.
Mounted on the vertical rotor drive shaft was the main gearbox for the tail shaft operating the two-bladed anti-torque rotor, with a diameter of 1.71 metres, the pitch of which was controlled by rudder pedals. This rotor's maximum rotational speed was 1200 r.p.m.
The three blades of the main rotor were made with tapered tubular spars and also connected to the root spars by a double-action hydraulic shock absorber.
Cyclic pitch control was obtained by a hanging stick while on the engine throttle support was the collective pitch control.
P.Lambermont "Helicopters and Autogyros of the World", 1958
Technical data for Model 3
Number of seats: 2, engine: 1 x Franklin 6AC-298 rated 165hp, rotor diameter: 9.14m, weight fully loaded: 544kg